1. Technical Field
The invention relates generally to methods of synthesizing silicon wires and, particularly, to a method of synthesizing silicon wires that employs metallic catalysts.
2. Discussion of Related Art
Since silicon is one of the most favored materials in the semiconductor industry and as it has been used in the IC industry for many years, much attention has already been paid to the research and synthesis of silicon wires. As early as in 1964, micrometer-scaled silicon whiskers grown on silicon substrates were synthesized by a Vapor-liquid-solid (VLS) method. Nowadays, VLS method is an important way to synthesize silicon wires. In this method, metals, generally selected from gold (Au), nickel (Ni) and iron (Fe), are employed as catalysts.
Although Au is a usual catalyst for silicon wires by the VLS method, the use thereof is limited by its expense. Furthermore, in the VLS method employing Au as a catalyst, poisonous and/or noxious matter is prone to be formed in the process, thereby forming pollutants that have to captured and, thus, increasing the environmental control costs associated therewith. The introduction of cheaper metals, selected from Fe and Ni, to catalyze the silicon wires has proven difficult over at least two issues. On the one hand, in the VLS method employing Fe or Ni as catalysts, high synthesizing temperature (i.e., above 1000° C.) is needed, thereby increasing the cost of the fabrication. On the other hand, the catalysts of Fe or Ni are prone to render unwanted impurities within semiconductor elements, thereby decreasing the performance thereof.
What is needed, therefore, is a method of synthesizing silicon wires that overcomes above-mentioned shortcomings, thus allowing them to be produced in a cost-effective manner.